Mobile turf instrument apparatus having driven, periodically insertable, ground penetrating probe assembly

ABSTRACT

A mobile turf instrument apparatus has a wheeled frame that may be propelled over the ground by a motive device, such as by a separate vehicle or by its own engine and drive train. A driven arm is carried on the frame and revolves in circles to periodically insert the probe(s) of a probe assembly into the ground during motion of the frame. The drive to the arm is momentarily disengaged when the probe(s) of the probe assembly are inserted into the ground. The probe assembly comprises two parts that rock relative to one another. Two soil measurement devices are connected to the probe assembly. A soil moisture sensor is coupled to the probe assembly for measuring soil moisture when the probe(s) are inserted into the ground. A load cell is responsive to the amount of rocking of the two parts of the probe assembly to measure soil compaction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of one or more previously filedcopending provisional applications identified as follows: ApplicationSer. No. 60/860,583 filed Nov. 22, 2006.

TECHNICAL FIELD

This invention relates generally to the field of turf maintenanceequipment. More particularly, this invention relates to equipmentcarrying instruments for measuring various parameters related to thehealth of the turf, such as soil moisture, soil compaction, etc.

BACKGROUND OF THE INVENTION

The turf maintenance field involves a wide range of equipment used topromote turf growth and to thereafter maintain the grass surface formingthe upper portion of the turf. For example, aerators are used to punchholes in the ground to relieve soil compaction in and beneath the turf.Mowers are used to cut the grass surface of the turf to a desiredheight. Fertilizers apply nutrients and pesticides to the turf toencourage grass growth and to prevent or limit damage to the grass byinsects.

In order to intelligently diagnose the health of the turf, variousmeasuring instruments are used to measure various parameters related tothe health of the turf. For example, many known soil moisture sensorsdetermine the moisture content of the soil using Timed DomainReflectometry (TDR). A TDR sensor involves sticking a probe assemblycomprising various probes into the ground. When the probes are pulsedwith electrical energy while they are inserted into the ground, areading can be taken from which the moisture content of the soil can bederived.

A penetrometer is a type of instrument used to measure soil compaction.Like the TDR sensor described above, a penetrometer has a probe assemblythat must be pushed into the ground in order for the penetrometer totake a reading. The penetrometer includes a load cell that measures theresistance the probe assembly encounters when entering the ground. Thisresistance is a measure of how compacted the soil is at the spot wherethe probe assembly has been inserted into the ground.

Other turf measurement instruments are known. A spectrometer known asthe GreenSeeker® uses light emitting diodes (LED) to generate red andnear infrared (NIR) light. The light generated is reflected off of thegrass surface of the turf and is measured by a photodiode. Red light isabsorbed by plant chlorophyll as an energy source during photosynthesis.Therefore, healthy turf absorbs more red light and reflects largeramounts of NIR than turf that is unhealthy. Thus, the GREENSEEKER®Instrument provides a measurement of the health or vigor of the turf.Other spectrometers besides the GreenSeeker® are also known in the art.

A turf measurement instrument like the GreenSeeker® spectrometeroperates without requiring physical penetration of the ground. Aspectrometer works simply by shining light at the turf and measuring thereflected light from the grass. Thus, in the past a spectrometer typeinstrument has simply been mounted on a mobile frame and driven over anarea of turf whose health is to be measured.

However, for a TDR soil moisture sensor, the probe assembly must beinserted into the ground in order for the device to operate. Thus, inthe past, such an instrument has traditionally been hand held with theprobe assembly being manually inserted or pushed into the soil atvarious desired spots. This is done by a walking operator who holds theinstrument in his or her hands and who manually pushes the probeassembly into the soil to undertake a soil moisture measurement and thenmanually pulls the probe assembly out of the soil at the conclusion ofthe measurement. This is a difficult and tiring task. Moreover, whenmeasuring the soil moisture content over a large area of turf, such as agolf course, it is extremely time consuming and laborious.

Penetrometers used to measure soil compaction have in the past beenmounted on vehicles rather than being hand-held. However, like a TDRsoil moisture sensor, the probe assembly of the penetrometer must beinserted into the ground in order to take a reading. Thus, with avehicle mounted penetrometer, the vehicle must be stopped at eachlocation where a reading is desired, the penetrometer must then beinserted into the ground, the reading is then taken, and then thepenetrometer must be pulled out of the ground, all with the vehicleremaining stopped. Then, and only then, can the vehicle be driven to thenext spot where a reading is to be taken. While the operator need notwalk the entire area to be measured, the need to stop the vehicle ateach spot where the penetrometer is to be inserted into the ground stillmakes the act of measuring a large area of turf a time consuming one.

SUMMARY OF THE INVENTION

One aspect of this invention relates to a mobile turf measurementapparatus. The apparatus comprises a frame propelled over the ground bya motive device other than a walking operator. A probe assembly ismovably carried on the frame such that the probe assembly has repeatingcycles of motion relative to the frame as the frame is propelled overthe ground with the probe assembly being lowered on the frame andapproaching towards the ground and being raised on the frame and movingaway from the ground during each cycle of motion. The probe assembly hasat least one probe that is inserted into the ground as the probeassembly moves towards the ground and that is extracted from the groundas the probe assembly moves away from the ground such that the probe(s)are inserted into the ground for a time interval lasting over only aportion of each cycle of motion of the probe assembly. A soilmeasurement device is operatively connected to the probe(s) of the probeassembly for measuring a parameter of the soil during the time intervalwhen the probe(s) have been inserted into the ground.

Another aspect of this invention relates to a mobile turf measurementapparatus. The apparatus comprises a frame supported for rolling overthe ground by at least one rotatable ground engaging member. A revolvingarm is carried on the frame for rotation about a substantiallyhorizontal axis of rotation. A first drive rotates the arm in complete360° revolutions about the axis of rotation as the frame is moved overthe ground. A probe assembly is carried adjacent one end of therevolving arm. The probe assembly includes at least one elongated probethat is inserted into the ground at some point in each revolution of thearm. A first soil measurement device is operatively connected to theprobe(s) of the probe assembly for measuring a parameter of the soilwhen the probe(s) have been inserted into the ground.

An additional aspect of this invention relates to a mobile turfinstrument apparatus. The apparatus comprises a frame that may bepropelled over the ground by a motive device. A probe assembly has atleast one probe. The probe assembly comprises two parts that rockrelative to one another. A soil moisture sensor is carried on the probeassembly for measuring soil moisture when the probe(s) are inserted intothe ground. A load cell is carried on the probe assembly and isresponsive to the amount of relative rocking of the two parts of theprobe assembly when the probe(s) are inserted into the ground to measuresoil compaction. A driven arm carries the probe assembly. The driven armis journalled on the frame for rotating about a substantially horizontalaxis to periodically insert the probe(s) of the probe assembly into theground during motion of the frame over the ground.

Yet another aspect of this invention relates to a probe assembly for usein taking soil measurements. The probe assembly comprises a first partand a second part pivotally secured to the first part to be able to rocktowards and away from the first part. At least one elongated probe ismounted on the second part with the probe(s) being inserted into theground to take soil measurements. A soil moisture sensor is operativelyconnected to the probe(s) for measuring soil moisture when the probe(s)are inserted into the ground. A load measuring device is provided whichdevice is responsive to the relative degree of rocking of the secondpart relative to the first part to be progressively more loaded as thesecond part progressively rocks towards the first part during insertionof the probe(s) into the ground to thereby measure soil compaction.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will be described hereafter in the Detailed Description,taken in conjunction with the following drawings, in which likereference numerals refer to like elements or parts throughout.

FIG. 1 is a perspective view towards the rear of a mobile turfinstrument apparatus according to this invention;

FIG. 2 is a perspective view towards the left front of the mobile turfinstrument apparatus of FIG. 1;

FIG. 3 is a perspective view towards the right front of the mobile turfinstrument apparatus of FIG. 1;

FIG. 4 is a perspective view of the probe assembly of the mobile turfinstrument apparatus of FIG. 1;

FIG. 5 is an exploded perspective view of the probe assembly of FIG. 4;

FIG. 6 is a perspective view of the revolving arm that periodicallyinserts the probe assembly of FIG. 4 into the soil; and

FIG. 7 is a side elevational view of the controls that engage anddisengage the drive to the revolving arm of FIG. 6 and that start andstop the taking of readings from various turf measurement instrumentscarried on the arm.

DETAILED DESCRIPTION

FIGS. 1-3 illustrate one embodiment of a mobile turf instrumentapparatus 2 according to this invention. Apparatus 2 comprises a mobileplatform or frame 4 supported for rolling over the ground by one or morerotatable ground engaging members, such as by a pair of wheels 6. Frame4 preferably comprises a tow frame having a forwardly extending tongue 8for allowing frame 4 to be hitched to a motive device in the form of atowing vehicle, such as a mower, utility vehicle, or the like.Alternatively, frame 4 could be pushed by the separate vehicle ratherthan being towed. Moreover, frame 4 could be self-propelled with themotive device comprising an engine or motor carried on frame 4.Counterweights 7 can be placed on frame 4, preferably at the cornersthereof, to add enough weight to frame 4 to prevent frame 4 frombouncing up and down as it is moved over the ground.

Apparatus 2 includes a revolving support in the form of an elongatedrevolving arm 10. Arm 10 is fixed to an inner end of a substantiallyhorizontal shaft 12 so as to rotate with shaft 12. Shaft 12 extends toone side of frame 4 such that an outer end of shaft 12 is located alongone side of frame 4. See FIG. 3. Shaft 12 is rotatably journalled onframe 4 by a pair of spaced bearings 14 carried on frame 4.

Arm 10 is positioned in an open central space in frame 4. In addition,bearings 14 are located high enough on frame 4 such that arm 10 canrevolve around the axis of shaft 12 and will clear the ground when doingso. The open central space of frame 4 is also large enough in afore-and-aft direction to accommodate the revolving motion of arm 10without arm 10 hitting any part of frame 4.

Arm 10 is revolved by a drive taken from one wheel 6 of frame 4. Thestub axle 16 that mounts such wheel 6 is long enough such that the innerend of stub axle 16 is located beneath frame 4 generally parallel to andbelow shaft 12. See FIG. 3. A first small drive sprocket 18 is carriedaround stub axle 16 and shaft 12 carries a second larger driven sprocket19, the two sprockets 18, 19 being connected together by a chain 20.Sprockets 18, 19 are sized to provide a speed reduction between therotational speed of wheels 6 and that of arm 10.

An electric clutch 22 is also carried on stub axle 16 to selectivelydrive stub axle sprocket 18. In other words, stub axle sprocket 18 iscoupled to stub axle 16 and is rotated by stub axle 16 when clutch 22 isengaged. Conversely, stub axle sprocket 18 is uncoupled from stub axle16 and is not being rotated by stub axle 16 when clutch 22 isdisengaged.

Referring now to FIG. 5, a probe assembly indicated generally as 24 isrotatably mounted on one end of arm 10. A pivot shaft 26 on probeassembly 24 extends through a bearing in a hub 28 on the end of arm 10.Pivot shaft 26 is non-rotatably keyed or splined to a small sprocket 30that is also carried on the end of arm 10. Rotation of probe assemblysprocket 30 relative to the end of arm 10 will also rotate probeassembly 24 relative to the end of arm 10.

The opposite end of arm 10 carries a weight 31. Weight 31 is heavierthan the collective weight of probe assembly 24 and sprocket 30 on theother end of arm 10. Thus, when apparatus 2 is stationary and arm 10 isnot being revolved by rotation of wheel 6, arm 10 will have a restingposition in which weight 31 is lowermost and probe assembly 24 isuppermost, i.e. arm 10 will be vertical and the end of arm 10 carryingweight 31 will be the lower end of arm 10 and the end of arm 10 carryingprobe assembly 24 will be the upper end of arm 10. This resting positionof arm 10 is not illustrated in the drawings.

Probe assembly sprocket 30 on the end of arm 10 is coupled by a chain 32to a fixed sprocket 34 that is carried concentrically around horizontalshaft 12 that rotates arm 10. Fixed sprocket 34 is so named because norotation of sprocket 34 is allowed relative to frame 4. Fixed sprocket34 is physically clamped or held relative to frame 4 so that it does notrotate. A rotatable idler sprocket 36 is mounted by a bracket 37 on arm10 substantially immediately beneath fixed sprocket 34. See FIGS. 1 and6. Idler sprocket 36 helps maintain proper tension on chain 32 duringrotation of arm 10.

As arm 10 rotates around horizontal shaft 12 in a given direction, chain32 produces an equal and opposite counter-rotation of probe assemblysprocket 30 so that probe assembly 24 always remains substantiallyhorizontal relative to frame 4 or to the ground during rotation of arm10. In other words, a reference mark 38 on the top of probe assemblypivot shaft 26 (shown in FIG. 5) will always remain on the top of shaft26 whether arm 10 is pointing straight up, straight down, forwards,backwards, or in any direction in between. Thus, probe assembly 24 isself-leveling relative to arm 10 as arm 10 rotates or revolves aroundthe axis of shaft 12.

In a complete revolution of arm 10, chain 32 translates or moves alongarm 10 by a distance equal to the number of teeth in fixed sprocket 34and probe assembly sprocket 30. Fixed sprocket 34 and probe assemblysprocket 30 are identical in size with the same number of teeth. Whilefixed sprocket 34 does not rotate relative to frame 4 or relative to theground, fixed sprocket 34 does rotate relative to arm 10 as arm 10revolves around the axis of shaft 12. One must remember that fixedsprocket 34 is concentrically positioned around shaft 12 to be on thesame axis as shaft 12, but fixed sprocket 34 is not rotatably coupled toshaft 12 and is not part of arm 10. Thus, the rotation of arm 10 doesproduce relative rotation between arm 10 and fixed sprocket 34.

Probe assembly 24 comprises two parts that are further mounted forpivoting relative to one another during operation of probe assembly 24.These two parts comprise an L-shaped bracket 40 having a side wall 42and a top rail 44 arranged at a perpendicular angle relative to sidewall 42. See FIG. 5. Pivot shaft 26 that mounts probe assembly 24 forpivoting on arm 10 is connected to an inner face of side wall 42 ofbracket 40. Top rail 44 of bracket 40 includes a recess, slot or cavity46 for holding a load cell 48, e.g. an Omega Engineering LC302-500 loadcell.

The other part of probe assembly 24 comprises a box-shaped housing 50with an open top. Housing 50 includes a bore 52 for receiving a pivotpin 54 carried on the outer face of side wall 42 of bracket 40, i.e. onthe face of side wall 42 that is opposite to the face that carries pivotshaft 26. Pivot pin 54 allows housing 50 to rock back and forth relativeto bracket 40.

Referring to FIG. 4, when bracket 40 and housing 50 are assembledtogether, top rail 44 of bracket 40 is juxtaposed substantiallyimmediately ahead of a front wall 56 of housing 50. Thus, load cell 48that is held on top rail 44 is positioned to abut with or be closelyspaced from front wall 56 of housing 50. As probe assembly 24 is pushedinto the ground, rocking of housing 50 about pivot pin 54, depicted bythe arrow F in FIG. 4, will vary the force exerted on load cell 48 byhousing 50.

A Timed Domain Reflectometer (TDR) soil moisture sensor package 58, e.g.a Campbell Scientific CS620, is carried by housing 50 of probe assembly24. Sensor package 58 includes a sensor body 60, a pair of groundpenetrating probes 62, a pair of probe mounting blocks 64, and aclamping plate 66. Each probe 62 includes a mounting collar 68 aroundthe upper end of probe 62 with the upper end of probe 62 stickingupwardly out of mounting collar 68. Each mounting collar 68 includes anannular, radially extending mounting flange 70. Probes 62 are metallicand mounting collars 68 may be made from any suitably strong and durablematerial, such as a composite material.

Mounting blocks 64 are provided as a separate pair of blocks 64 to allowblocks 64 to be separated for installation of probes 62. Each mountingblock 64 includes a pair of semi-circular grooves 72 with a horizontalchannel 74. Each groove 72 is sized to conform to the outer diameter ofmounting collar 68 on the upper end of probe 62. Each channel 74 issized to receive a mounting flange 70 on collar 68. Each mounting block64 is made of an electrically non-conductive material, such as ABSplastic.

Mounting collars 68 of probes 62 are placed into grooves 72 and channels74 of one mounting block 64. Then, the other mounting block 64 issuperimposed over probes 62 and abutted with the first mounting block 64to clamp probes 62 between the two mounting blocks 64. Clamping plate 66is then bolted or screwed to housing 50 to clamp both mounting blocks 64to the underside of the floor 76 of housing 50. When so mounted, probes62 will extend downwardly away from housing 50 through openings 78 inclamping plate 66 that are large enough to receive probes 62.

The upper ends of probes 62 project upwardly far enough to reach sensorbody 60. Sensor body 60 is positioned or held within housing 50 of probeassembly 24. Sensor body 60 is provided with a pair of threaded probeconnections 78 on the bottom of sensor body 60 for receiving the upperthreaded ends of probes 62 to establish both a mechanical and electricalconnection to probes 62. See FIG. 5. Sensor body 60 can reach the upperends of probes 62 through a slot 80 provided in floor 76 of housing 50.Thus, effectively sensor body 60 is carried on the upper ends of probes62 with the upper ends of probes 62 sticking up into probe connections78 on sensor body 60. Probes 62 are preferably first inserted throughslot 80 and screwed into sensor body 60 while sensor body 60 sits inhousing 50 and then mounting blocks 64 are abutted around probes 62beneath housing 50 with clamping plate 66 finally being bolted tohousing 50 to hold everything in place.

The upward force exerted on probes 62 as they are inserted into theground, represented by the arrow U in FIG. 4, is transmitted throughmounting collars 68 and mounting blocks 64 to the underside of housing50. Thus, damage to sensor body 60 from the force U generated duringprobe insertion is either eliminated or greatly reduced. Mountingcollars 68, mounting blocks 64, and how mounting blocks 64 are abuttedand bolted to housing 50 are a simple and durable mounting system forprobes 62 and sensor body 60.

It should be clear that both load cell 48 and sensor body 60 areelectrically connected to various control and measurement electronicslocated elsewhere. These electrical connections are diagrammaticallyillustrated by electrical wires 82. Thus, the readings that are derivedfrom load cell 48 and sensor package 58 can be logged or recorded in anyappropriate device, such as a data logger or computer (not shown). Thecomputer may be carried on frame 4 itself, or on the vehicle used to towthe frame 4, and may be hardwired to load cell 48 and sensor body 60 assuggested by wires 82. Alternatively, wireless communication could beestablished between load cell 48 and sensor body 60 to allow thereadings to be wirelessly communicated to the computer.

As frame 4 moves across the turf, and when clutch 22 is engaged, arm 10will rotate or revolve from the drive taken from wheel 6. As arm 10revolves, probe assembly 24 rotates correspondingly in a way thatmaintains probe assembly 24 in a horizontal position with probes 62facing the ground. At some point, arm 10 will approach the ground andprobes 62 will be pushed into the ground.

Clutch 22 can be disengaged to uncouple arm 10 from the drive from wheel6 from some time shortly before probes 62 have entered the ground(assuming arm 10 has sufficient momentum) to some time shortly afterprobes 62 have entered the ground. If clutch 22 is disengaged shortlybefore probes 62 have entered the ground and the speed of the arm ishigh enough, then the momentum of arm 10 will be sufficient to cause arm10 to continue to rotate and to insert probes 62 in the ground. Onceprobes 62 are inserted into the ground, then arm 10 will still continueto rotate since probes 62 are now stuck in the ground but frame 4 iscontinuing its forward motion. Thus, when the drive is actuallydisconnected from arm 10 from a moment just prior to or just after probeinsertion and/or during the entire time probes 62 are in the ground, arm10 will to the naked eye look like it is revolving as before.

There are two reasons for disconnecting the drive to arm 10 while probes62 are inserted into the ground. One is to avoid having probes 62 makeelongated holes or slots in the ground. The other is to avoid puttingtoo much torque or stress on probes 62 or on the other components ofsensor package 58 while probes 62 are in the ground. This will furtherhelp avoid damaging probes 62 or the other components of sensor package58.

In any event, the drive disconnection to arm 10 lasts only so long asprobes 62 are in the ground. When arm 10 swings around past bottom deadcenter and probe assembly 24 is about to begin to lift probes 62 out ofthe ground, clutch 22 is reengaged. This couples arm 10 to the drivefrom wheel 6 to continue the rotation of arm 10 again.

When probes 62 of probe assembly 24 are in the ground, electrical energycan be supplied to probes 62 from the control electronics to initiate asoil moisture measurement. This measurement will then be reported backto the computer as described above and will be recorded. A GPS device 84or other global locating device can be carried on frame 4. Thus, thereported soil moisture reading can be correlated to the location wherethe reading was taken.

This is also true of the readings of any other turf parameters that willbe taken and recorded. Such readings will similarly be correlated to theGPS location of frame 4 at the time they are taken. Thus, an accuratemap can be made of the turf area over which frame 4 is moved which mapwill display the various readings of the measured turf parameters andwhere such readings occurred.

Load cell 48 positioned between housing 50 and bracket 40 of probeassembly 24 is used to measure soil compaction when probes 62 are beinginserted in the ground. This is so because the force exerted on loadcell 48 by housing 50 will vary depending upon the hardness of theground. The rocking action of housing 50 determines the force on loadcell 48 and the rocking action varies depending upon the hardness of theground. Housing 50 will rock more during probe insertion when the groundis hard as opposed to when the ground is soft. Thus, a measurement ofsoil compaction can be taken and recorded along with the soil moisturereading. Thus, the same probe assembly 24 does double duty since itfunctions both as part of a penetrometer used to measure soil compactionas well as part of a soil moisture sensor.

Referring now to FIG. 7, a plurality of limit switch controls 86 aremounted in a fixed position on frame 4 along an arcuate flange 88.Flange 88 is positioned symmetrically relative to the top dead centerposition of arm 10 as shown in FIG. 7. Each limit switch 86 senses or istriggered by a magnetic or other trigger 90 carried on arm 10. Thus, asarm 10 revolves in the direction of rotation indicated by the arrow A inFIG. 7, limit switches 86 will be selectively closed in sequencebeginning with the first limit switch 86 _(a) and ending with the fourthlimit switch 86 _(d).

The first and fourth limit switches 86 _(a) and 86 _(d) control theengagement and disengagement of clutch 22 respectively. In other words,when the first limit switch 86 _(a) is tripped shortly after probeassembly 24 enters the ground, clutch 22 will be disengaged. As thefourth limit switch 86 _(d) is tripped as probe assembly 24 just beginsto lift out of the ground, clutch 22 will be engaged. The precisepositioning of the first and fourth limit switches 86 _(a) and 86 _(d)can be adjusted by sliding them back and forth in arcuate slots 92carried on flange 88. This allows the user to adjust the disengagementof clutch 22 to correspond to when probes 62 have just been insertedinto the ground and to adjust the engagement of clutch 22 to when probes62 are just about to lift out of the ground.

The second and third limit switches 86 _(b) and 86 _(c) signal to thecontrol electronics when to start and stop the soil moisture and soilcompaction sensing. Sensing starts when second limit switch 86 _(b) istripped. Sensing stops when third limit switch 86 _(c) is tripped. Thesecond and third limit switches 86 _(b) and 86 _(c) could be replaced,however, with a time delay following tripping of first limit switch 86_(a). In other words, sensing could start and stop during apredetermined time interval that begins after a predetermined time delayfollowing the tripping of first limit switch 86 _(a).

In addition to measuring and recording parameters that are derived fromthe insertion of probe assembly 24 into the ground, frame 4 could carryother turf instruments that do not depend upon such an insertion. Forexample, a spectrometer 94 for measuring the health of the grass couldbe mounted on frame 4 at any suitable location, such as on a post 96 onthe rear of frame 4. As frame 4 moves over the ground, spectrometer 94measures the vigor or health of the turf using light reflectance asdescribed in the Background of the Invention section of thisapplication. Such a turf health measurement reading would then becorrelated to the GPS location of frame 4 and stored with the soilmoisture and soil compaction readings in the overall map of the turfarea being surveyed. These turf health measurement readings could betaken at the same time as the soil moisture or compaction readings or atdifferent times.

Apparatus 2 of this invention provides for measuring various parametersof the turf using a probe assembly 24 that is periodically inserted intoand removed from the ground. It does so, however, by mounting such aprobe assembly on a mobile frame to allow the readings derived fromprobe assembly 24 to be accomplished automatically and without effort bythe operator as frame 4 is driven or otherwise moved over the turf areato be surveyed and measured. This greatly enhances the productivity ofthe operator. The operator need not walk the turf area by foot and sticka hand held soil moisture sensor into the ground. The vehicle need notbe stopped to allow the probe assembly to be inserted into the ground.

In addition, frame 4 can be used to carry other turf measurementinstruments, such as spectrometer 94, that measure other turf parametersusing methods that do not require physical penetration of the ground orin fact any engagement with the turf or the ground. Thus, apparatus 2 ofthis invention can provide a whole range of turf parameter measurementsand record and map such measurements over the turf area being surveyed.Obviously, sensors other than those described herein for measuring otherturf parameters could be added to frame 4 of apparatus 2. For example,instruments for measuring soil salinity or canopy temperature could beadded.

Various modifications of this invention will be apparent to thoseskilled in the art. While a simple mechanical drive from wheel 6 ispreferred for rotating arm 10, arm 10 could be driven by a separatehydraulic or electric motor. Soil moisture sensors other than TDR soilmoisture sensors could be used. Thus, this invention is not limited tothe specific details of the embodiment disclosed herein.

1. A mobile turf measurement apparatus, which comprises: (a) a framepropelled over the ground by a motive device other than a walkingoperator; (b) a probe assembly movably carried on the frame such thatthe probe assembly has repeating cycles of motion relative to the frameas the frame is propelled over the ground, wherein the probe assembly islowered on the frame and moves towards the ground and is raised on theframe and moves away from the ground during each cycle of motion; (c) atleast one probe carried on the probe assembly with the probe(s) beinginserted into the ground as the probe assembly moves towards the groundand being extracted from the ground as the probe assembly moves awayfrom the ground such that the probe(s) are inserted into the ground fora time interval lasting over only a portion of each cycle of motion ofthe probe assembly; and (d) a soil measurement device operativelyconnected to the probe(s) of the probe assembly for measuring aparameter of the soil during the time interval when the probe(s) havebeen inserted into the ground.
 2. The apparatus of claim 1, wherein theprobe assembly is oriented with the probe(s) substantially continuouslyfacing the ground during the repeating cycles of motion.
 3. Theapparatus of claim 1, further including a drive for propelling the probeassembly through the repeating cycles of motion, wherein the drive isdisengaged for a substantial portion of the time interval.
 4. A mobileturf instrument apparatus, which comprises: (a) a frame supported forrolling over the ground by at least one rotatable ground engagingmember; (b) a revolving arm carried on the frame for rotation about asubstantially horizontal axis of rotation; (c) a first drive to rotatethe arm in complete 360° revolutions about the axis of rotation as theframe is moved over the ground; (d) a probe assembly carried adjacentone end of the revolving arm, wherein the probe assembly includes atleast one elongated probe that is inserted into the ground at some pointin each revolution of the arm; and (e) a first soil measurement deviceoperatively connected to the probe(s) of the probe assembly formeasuring a parameter of the soil when the probe(s) have been insertedinto the ground.
 5. The apparatus of claim 4, wherein the probe assemblyis rotatably carried on the arm, and further including a second drive torotate the probe assembly in a direction counter to the direction ofrotation of the arm as the arm is revolving to thereby keep the probe(s)of the probe assembly substantially facing the ground.
 6. The apparatusof claim 5, wherein the second drive comprises an endless memberentrained around a portion of the frame and a portion of the probeassembly for producing the counter rotation of the probe assembly fromthe revolving motion of the arm as the first drive rotates the arm. 7.The apparatus of claim 6, wherein the second drive comprises: (a) afirst toothed sprocket non-rotatably coupled to the probe assembly suchthat rotation of the first toothed sprocket rotates the probe assemblyon the arm; (b) a second toothed sprocket fixed to the frame, whereinthe first and second sprockets have the same number of teeth; and (c)wherein the endless member is a chain entrained around the first andsecond toothed sprockets.
 8. The apparatus of claim 7, wherein thesecond toothed sprocket is fixed to the frame and lies along the axis ofrotation of the arm.
 9. The apparatus of claim 4, further including aclutch for disengaging the first drive at least during a substantialportion of a time interval defined between a first moment in time whenthe probe(s) are inserted into the ground and a second moment in timewhen the probe(s) are extracted from the ground during each revolutionof the arm.
 10. The apparatus of claim 9, further including a pair offirst and second circumferentially spaced limit switches carried on theframe adjacent an orbital path of the arm as the arm revolves on theframe, wherein the first and second limit switches are tripped by thearm as the arm revolves to control the clutch to thereby sequentiallydisengage and reengage the first drive.
 11. The apparatus of claim 4,wherein the first drive is powered from at least one of the groundengaging member(s) of the frame.
 12. The apparatus of claim 11, whereinthe first drive includes a speed reduction such that the arm revolvesmore slowly than the speed of rotation of the ground engaging member(s)from which the first drive is powered.
 13. The apparatus of claim 4,further including a weight carried adjacent an end of the arm oppositeto the end of the arm carrying the probe assembly, wherein the weighthas a mass sufficiently high such that the end of the arm carrying theprobe assembly will be elevated to a raised, substantially verticallyupright position when the arm is at rest and the first drive forrevolving the arm is not operating.
 14. The apparatus of claim 4,wherein the first soil measurement device is selected from a group ofdevices comprising a soil moisture sensor and a soil compactionmeasurement device.
 15. The apparatus of claim 14, further including asecond soil measurement device operatively connected to the probe(s) ofthe probe assembly for measuring a parameter of the soil when theprobe(s) have been inserted into the ground, wherein the first soilmeasurement device comprises the soil moisture sensor and the secondsoil measurement device comprises the soil compaction measurementdevice.